The present invention generally relates to the controlled lowering of a heavy object and, in particular, to the controlled lowering to the ground of a severed portion of a tree.
An arborist is one that is involved in the care of trees. This often involves trimming and pruning branches that are high off the ground as well as removing trees once they are dead or damaged. In addition, such trees are often in landscaped areas such that it is preferable not to allow a severed branch to drop to the ground because the falling severed portion may cause indentions in a well manicured lawn or may fall on something fragile below, such as shrubbery or anything that would be damaged by the falling weight of the severed branch. To avoid these consequences, an arborist may use ropes to lower a severed portion of the tree to the ground in a controlled manner.
Many devices are known that facilitate the lowering of a severed portion of a tree to the ground. Such devices, for example, are disclosed in U.S. Pat. Nos. 4,239,188; 5,971,363; 5,484,253; and U.S. Pat. No. Des. 330,671. Except for the tree pulley of U.S. Pat. No. Des. 330,671, all of the disclosed devices provide for and/or require the wrapping of a lowering rope multiple times around a portion of the device for sufficient frictional support of the severed portion of the tree for controlled lowering of thereof, especially when the severed portion of the tree is heavy. This is unfortunate, because it is believed that every complete wrapping of the lowering line around a portion of the device creates a twist in the line, which decreases the useful life of the line and limits the number of times the line may be used to lower portions of trees to the ground. Furthermore, the wrapping of the lowering line creates a tendency in the lowering line to twist and to knot, which creates a hazard during lowering operations. A twisting or knotting of the lowering line may jam a device through which the lowering line passes. An unobservant operator quickly passing the lowering line through his hands also may be unexpectedly thrown off balance or injured when a knot suddenly is encountered.
Accordingly, a need exists for a device for lowering a severed portion of a tree to the ground that does not require the creation of twists in the lowering line for controlled lowering of the severed portion of the tree.
Briefly described, the present invention relates to an apparatus and method for lowering a severed portion of a tree to the ground. In a first aspect of the present invention, the apparatus includes a rope and a device comprising an anchor having an arrangement of guiding protuberances. Three of the guiding protuberances define a triangular arrangement. Each of the guiding protuberance includes a bearing surface frictionally engaging and redirecting the rope without the rope fully encompassing any portion of the anchor, including any of the guiding protuberances. No twist thereby is created in the rope in the controlled lowering of the severed portion of the tree to the ground.
In a feature of the anchor, two rows of guiding protuberances are provided with each row including a plurality of guiding protuberances, with adjacent guiding protuberances in each row extending from the anchor in generally parallel relation to the other. In another feature, the anchor includes a first member secured in engagement with a lower portion of the tree against movement relative thereto, and a second member pivotally connected to the first member along a pivot axis and including thereon the guiding protuberances. In another feature, the anchor includes a braking pin extending at an acute angle to a surface of said anchor such that a gradually diminishing spacing is defined. A portion of the rope then may be extended through and wedged therebetween against movement relative to the guiding protuberances.
In another aspect of the present invention, the apparatus includes a device comprising an anchor having an arrangement of guiding protuberances with each guiding protuberance including a bearing surface for frictional engagement with and redirection of a rope around an axis thereof. In particular, a first guiding protuberance is disposed in proximity to an intermediate guiding protuberance defining a segment of a rope path therebetween, and a second guiding protuberance is disposed in proximity to the intermediate guiding protuberance defining another segment of the rope path therebetween without the segments crossing. The axis of the first, second, and intermediate guiding protuberances are generally non planar (i.e., do not extend within a plane common to all three axis). In features of this aspect, each segment extending between the bearing surfaces of the guiding protuberances generally is linear; the guiding protuberances extend from the anchor in generally parallel relation to each other; the axis of the first, second and intermediate guiding protuberances extend in parallel relation to one other; the bearing surfaces of the guiding protuberances generally are disposed in alignment with one another such that the segments generally are coplanar.
In another aspect of the present invention, an apparatus for the controlled lowering to the ground of a freshly cut upper portion of a tree includes a mounting member attachable to the tree; and a guiding member pivotally connected to the mounting member along a pivot axis and including an arrangement of guiding protuberances generally extending to one side thereof, with each guiding protuberance having a bearing surface for frictional engagement with and redirection of a rope. In a feature of this aspect, the guiding member includes a second arrangement of guiding protuberances extending to another side thereof. Preferably in this aspect, the guiding member includes oppositely facing planar surfaces generally parallel to the pivot axis, with the protuberances of the first arrangement extending from the first planar surface and the protuberances of the second arrangement extending from the second planar surface. Furthermore, the first arrangement of protuberances preferably is a mirror image of the second arrangement of protuberances, the protuberances extend generally orthogonal to the pivot axis; the protuberances have differing cross-sectional areas; and the arrangement comprises an array of protuberances including rows and columns. The columns of protuberances also preferably are offset to one another.
In additional features of these aspects of the present invention, the guiding protuberances include rollers and the anchor includes a winch for controlled rotation of the rollers. Alternatively, the rollers include sprockets, and a chain operatively connects the rollers with the winch for controlled rotation. A motor may be included for operation of the winch. In another feature of these aspects, the device further includes an arm attached to and extending away from the anchor, with the arm including a distal end having a guiding surface for guidance of the rope away from the anchor. In this regard, a pulley is secured on the distal end of the armxe2x80x94the pulley including the guiding surface. Also, the arm may be telescopic. In other features of these aspects of the present invention, the guiding protuberances each have generally circular cross-sections, and the circular cross-sections have different cross-sectional areas. Additionally, each guiding protuberance includes an end configured to bar slippage of the rope out of engagement with the bearing surface thereof. The end may include a pin mounted thereon and extending beyond opposite sides of the guiding protuberance or a flange.
Also in accordance with the present invention, a method of lowering to the ground a first portion of a tree includes the steps of securing one end of a rope to the first portion of the tree; securing an anchor against movement relative to another portion of the tree; guiding an intermediate length of the rope around each one of a triangular arrangement of guiding protuberances of the anchor for support of the first portion of the tree once severed, each guiding protuberance including a bearing surface frictionally engaging and redirecting the rope without the rope fully encompassing any portion of the anchor including any of the guiding protuberances; severing the first portion of the tree; and controlling movement of the rope past the guiding protuberances.
In features of this aspect of the present invention, the method further includes the steps of not twisting the rope during the step of guiding the intermediate length of the rope around the guiding protuberances; restraining the rope against movement relative to the guiding protuberances by wedging the rope between a surface of the anchor and a braking protuberance that extends from the surface of the anchor at an acute angle; guiding the rope near to the ground with a pulley attached to an arm extending downwardly away from the anchor.
In yet an additional feature of this aspect, the method further includes independently lowering an additional portion of the tree by securing one end of another rope to the additional portion of the tree; guiding an intermediate portion of the other rope around each one of a second arrangement of guiding protuberances for support of the additional portion of the tree once severed, each guiding protuberance including a bearing surface frictionally engaging and redirecting the other rope without the rope fully encompassing any portion of the anchor including any of the guiding protuberances; severing the additional portion of the tree; and controlling movement of the other rope past the guiding protuberances. In this case, the first arrangement and second arrangement of guiding protuberances are part of the same device.
In a preferred embodiment of the device of the present invention, a plurality of cylindrical protuberances for distributing frictional resistance to the lowering line are disposed parallel to one another and extend from and are attached to a planar distribution plate. The planar plate is attached to a base plate, which may be curved to conform to the curved outer surface of a tree trunk, or any object to which the lowering device may be attached during operation. The protuberances provide a route for a lowering line to pass through, with the end of the lowering line extending out of the device, thereby allowing an operator to be positioned away from the device, even when the device is attached to a tree trunk. The protuberances are strategically arranged on the planar plate so that the lowering line frictionally slides along the surfaces of the protuberances, but without fully wrapping around any particular protuberance. Advantageously, the line is prevented from the twisting that occurs when a lowering line is wrapped completely at least once around an object. Each protuberance progressively adds friction to the line as it passes through the device, without the line being fixed to the device. Since the line is not fixed to the device, the line can pass through the device and can be manually regulated by an operator at the unattached end of the line.
Additionally, in a preferred embodiment of the device, the planar plate is hingedly attached to the base plate so that the lowering line can exit from the device over a range up to approximately 180 degrees. This provides the operator with a range of options with respect to the location of the operating while operating the device. The device also includes a retaining pin or flange at the end of the protuberance to prevent the lowering line from slipping off the end of a given protuberance as the line frictionally slides through the device. This is especially helpful when the planar plate is oriented to either the right or left of perpendicular with respect to the base plate.
In another preferred embodiment, a series of sprockets and chain or gears are provided in a winch mechanism to facilitate the controlled lowering of the severed portion of the tree or for raising heavy objects, such as a chainsaw or other cutting tool. The sprockets or gears are attached to the protuberance, which are designed to rotate freely in apertures, which are designed to receive the protuberance tubes in the distribution block. The ratios of the gears or sprockets may be selected to allow a mechanical advantage for raising the object while at the same time providing resistance to the weight being raised, so that if the operator releases the winch, the weight of the object being raised will not cause it to fall. This feature can also be achieved with the use of a pawl or similar device known in the art.